7. Application of a Split-Type Obturator Retained by Magnetic Attachments

K.Kanada, M.Onuki and T.Hosoi

Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine（Japan）

Introduction

Maxilla-defects following tumor resection are often broad, making dento-maxillary prostheses very difficult to use to correct defects. This is because it is difficult for such a prosthesis to stay in the mouth or a large obturator to be put on and taken off. Here, the use of a split obturator and dento-maxillary prosthesis in a patient with broad maxilla-defect solved the above-mentioned problem, and favorable results were obtained.

Case

Patient: A 76-year-old male

Chief complaint: Visited our University Dentistry Hospital for the first time in March 2007 complaining of an inability to eat because his denture kept falling off.

History of present illness: The patient underwent surgery to remove maxillary sinus cancer in 1988, then received radiotherapy. The patient has since been wearing a dento-maxillary prosthesis.

Present illness: The maxilla was edentulous (Aramany class I). No teeth were missing from the mandible (Fig. 1).

Denture preparation

Impressions of the denture and obturator sections were taken separately.
For the obturator section, a tubular coustom tray was first made using resin, then Denture Aid LC (GC, Japan) was applied in the mouth as widely as possible and cured to complete the tray.
In terms of impression-taking, a silicone impression material (Fusion mono-phase type GC, Japan) was used, then a wash-type impression material was used to take an impression of finer areas (Fig. 2).
After interocclusal record and trial fitting, a resin was poured into the denture section and obturator (Fig.3).
The impression of the junction between the denture and obturator was taken inside the mouth. First, the obturator section was attached in the mouth, then the silicone impression material (Fusion mono-phase type GC, Japan) was poured, and the patient was instructed to bite gently (Fig.4).
The junction between denture and obturator was set near the denture basal surface, and a circumferential groove was formed (Fig. 5).
As retainers, Phsyiomagnets (Nisshin, Japan) were used, with 4.8-mm diameter magnets placed in the anteroposterior regions, 3.0-mm diameter magnets placed in the left-right regions, and keepers placed on the obturator to complete the denture (Figs. 6, 7) .

Results and Discussion

Retentive force of the dento-maxillary prosthesis was sufficiently high, and the chief complaint of dentures falling out while eating was solved. Masticatory and speech disorders were also improved and esthetically favorable results were obtained. The patient is now able to easily put on and take off the dento-maxillary prosthesis independently, and oral hygiene has remained favorable. Denture function tests showed that functions markedly improved with the new denture when compared to the old denture.

Functional assessment

After attaching the new denture, various function tests and surveys were conducted, and therapeutic effects were assessed.

Masticatory function

Maximum bite force

Using Dental Prescale 50H/R type (Fuji Film, Japan), maximum bite force was measured using the old and new dentures and results were compared.

Maximum bite force for the old and new dentures was 207.8 and 418.1 N, respectively .

Masticatory scores

An ability of mastication was measured using chewable foods on Yamamoto's bite table. Most scores were better when compared to the old dentures (Fig. 9).

Patient subjective satisfac

Figure 10 shows the results of subjective satisfaction for denture and oral functions.

Level of satisfaction was high for all items.

Conclusions

In the present patient, a split-type obturator was used, achieving large retentive force. Cleaning inside an obturator is often difficult with a dento-maxillary prosthesis, but cleaning in this case was very easy, because the patient is able to take apart the prosthesis independently and the design is simple.

In addition, a circumferential groove was added to the junction between the obturator and denture to prevent water invasion into the obturator.

In the present method using a split obturator, location of the split and magnet retentive force need to be examined.

Discussion Board